Playground static-assets example throws ReferenceError on Submit because message is undefined, hidden by another example's ambient global #1805

The playground's "Interactive Instrument with Static Assets" example can never be completed. Its Submit handler calls done({ message }), but nothing in the instrument defines message, so clicking Submit throws ReferenceError: message is not defined and done is never called. Type-checking does not catch it, because a different example, Interactive-With-Legacy-Script/legacy.d.ts, declares declare let message: 'hello' as an ambient global. That declaration is in scope for every file under apps/playground/src, so tsc (and pnpm lint) accept the undefined identifier.

Where

apps/playground/src/instruments/examples/interactive/Interactive-With-Static-Assets/index.ts:18-23:

render(done) {
  const button = document.getElementById('submit-btn')!;
  button.addEventListener('click', () => {
    done({ message });
  });
},

The global that hides it, apps/playground/src/instruments/examples/interactive/Interactive-With-Legacy-Script/legacy.d.ts:1:

declare let message: 'hello';

fragment.html has no element with id="message" either, so no named-element global exists at runtime.

Reproduce

1. Open the playground and select Examples → Interactive Instrument with Static Assets.
2. Click Submit in the preview.

Actual: the browser console shows ReferenceError: message is not defined, and the instrument never completes.
Expected: the instrument completes with a message string that satisfies its validationSchema.

Tests

The playground's vitest project only covers pure modules, so the e2e test is the guard: in testing/src/specs/playground.spec.ts, select this example, click Submit in the preview frame, and assert that the instrument reaches its completed state.

Suggested fix

Pass a literal, e.g. done({ message: 'Hello' }). Then scope the legacy example's ambient declaration so it cannot mask undefined identifiers in other examples, for example by declaring it as window.message (declare global { interface Window { message: 'hello' } }) and reading it as window.message in that example.